Where are the Pink and White Terraces of Lake Rotomahana?

In 2018, Bunn and Nolden published a paper purporting to have established the true position of the Pink and White Terraces of Lake Rotomahana using forensic cartography, ‘reverse engineering’ an 1859 compass survey of Ferdinand von Hochstetter. Their results suggest that the terraces are buried partly on land, near the present-day lake shore.

Sightlines constructed using an 1881 Charles Spencer photograph overlooking the White Terraces towards distant Maungaongaonga and Maungakakaramea, and replicated by us, show the location of the White Terraces by Bunn and Nolden to be untenable. Fitting the pre-1886 eruption outline map of Lake Rotomahana of Keam (2016. The Tarawera eruption, Lake Rotomahana, and the origin of the Pink and White Terraces. Journal of Volcanology and Geothermal Research 314:10–38.) to our high-resolution bathymetry shows a remarkable fit of the shoreline around the Pink Terraces area to distinct bathymetric features. Side-scan sonar images of inferred tiers of Pink Terraces (de Ronde CEJ, Scott BJ, Leonard GS, Calvert AT. 2016a. Evolution of the sublacustrine geothermal system of Lake Rotomahana, New Zealand: effects of the 1886 Mt. Tarawera eruption—an introduction. Journal of Volcanology and Geothermal Research 314:1–9.) show they sit where the map of Keam would have them lie.